Improvement in sewing-machines



T. 1. w. ROBERTSON.

Sewing Machine.

' Patented Feb. 10 1857.

III-In. II

FIG. 3.

UNITED STATES PATENT OFFI Ea THOS. J. w. ROBERTSON, OF NEW YORK, N.'Y.

. IMPROVEMENT IN SEWING-MACHINES.

Specification forming part of Letters Patent No. 16,609, dated February10, 1857.

To all whom it may concern.-

Be it known that I, THOMAS J. W. ROBERT: sON, of the city, county, andState of New York, have invented certain new and useful Improvements inSewing-Machines; and I do hereby declare that the following is afull,clear, and exact description of the same, reference being made to theannexed drawings, making a part of this specification, in which FiguresI and II are elevations. Figs. III, IV, and V are views of parts indetail; and similar letters indicate similar parts throughout thefigures.

My invention consists, principally, in the following particulars:

First, in the cutting of a spiral groove from the eye of the needle,(which is located near the point, as usual,) in an upward direction, andso as to extend from one-fourth to onehalf of the circumference thereof.The use of this groove is to insure that the looper shall always takeinto the loop by reason of the angular direction in which the threadlies in the said groove. It must therefore always cross the point of thelooper and be taken up, as will be described.

Secondly, in the adaptation of a piece which I call a loop-guide, theobject of which is to turn over the loop and cause it to lie in a goodposition for passing easily over the looper, as will be made to appear.

Thirdly, in a safety loop-guard, the use of I which is to keep the loopunder the table and in position either in case of its slipping over thetop of the looper before the succeeding stitch is taken, or if thelooper should miss taking into it at all.

The machine is constructed substantially after the same plan asdescribed in certain Letters Patent granted to me, being No. 12,577. Theneedle has a spiral groove starting from the eye on the outer side andwinding upward for a distance about equal to the stroke of the needle,and in that space winds nearly half round the saine, and as seen at a,Fig. III. The needle is set so that the eye shall point diagonally withreference to the sewing-table, and so that the spiral groove will faceoutward. The thread lies in this groove, and as the point of the looperb, curving round, is so placed as to lie about centrally to the path ofthe needle and close to it, that point must during the vibrations of theneedle necessarily cross the groove, whereby the moment the needlecommences its upward stroke and the loop puffs out the point of bwill,as the needle rises, go through the loop by reason of crossing thepath of the thread, as will be clearly seen by the duplicate or bluelines in Fig. III. After the point has entered, the loop-guide will comeinto play. This is a piece of wire curved into a peculiar shape, andprojecting from the front plate under the table, so that the point willcome around the needle and terminate just in front of the looper b, asseen at c in the several figures. The curve of this Wire is such that ithasan inclined upward slant over the looper, and the use of it is toprevent the loop from puffing directly out, and to cause it to lie wellover the looper b,whereby the loop can slip easily onto the straightpart of the same. But for this the loop would in its rapid motion upwardbe apt to draw hard upon the point of b, where the angle is somewhatabrupt, and bind there. At this part of the machine is also situated theloopguard, being a pin or bar projecting out from the end plate justbeneath the table, and so placed as to cross the hole where the needlepasses through, leaving just clearance for the latter to pass by, asshown more clearly in the detached view at c, Fig. V, wherein also isshown the position of a loop which may have either slipped off the topof the looper before it ought, or which was not taken upon it at all.The pin 6 therefore, keeping the loop horizontal, as the feed goes on,prevents the loop from being carried along to the opposite side of theneedle-hole, so that the loop is still kept horizontal and close in thepath of the needle on its downstroke, and the stitch is not thereforedropped.

An improvement in the tension apparatus is seen in Figs. I and II. Itconsists of a spring, i, pressing against the flat head of thefriction-pin i, and covering the hole 0 through that where the threadpasses in. Through the spring-plate there is also a hole, 0, situated onone side, and so as to lie near the edge of the head of the pin. Throughthis the thread is first rove on its way from the spool to. thefriction-pin, passing thence underneath the spring to the hole 0 in saidpin. Thus it lies along the face of the head a short distance, af-

fording space for the spring to bind or pinch to play. This, as seen inFig. V, represents the same. The use of this is to prevent the slackbetween the spool and the friction-pin from loosening on the said pin,and thereby destroying the proper tension required to be alwaysmaintained thereon.

The operation is as follows As the needle descends the thread which liesin the spiral groove is carried past the point of the looper, the latterriding over it and standing at the end of the stroke above the grooveand at a plain part of the needle; but it will be seen that the red linerepresenting the thread in position while the needle is descending liesacross the point of the looper. Thus the moment that the upward strokecommences, whereby the thread is slackened and puffs out of its groove,that thread will be in position to insure the entrance of the looper,and as shown by the duplicate line in blue. At this point the loop-guidecomes into play to throw the loop over to one side and flatten it, sothat the body of the looper will pass easilythrough without strainingupon the angular or rounded part near the point. If in its upward ascentthrough an unusual speed, jerk, or other deranging cause. the loopshould pass entirely over and get clear of 1) before the next downstrokeof the needle the guardpin 0 comes inthe loop 6 either as having escapedthe looper entirely or as having slipped off it, and being held openjust in range of the needle, so that the latter will go through thesame, as it would were the loop retained upon 6, and the stitch will nottherefore be dropped. The tension arrangement is such that the precisestrain required may be had during the operation, as

the pin may be turned and more or less thread wound round its shankwithout interfering with the spring-clamp at its head, so that. theslack between the spool and spring will never affect the tension beyond,and it cannot kink between that point and the needle.

1. The spiral groove in the needle, leading upward from the eye on oneside, in combination with the looper, in the manner and for the purposedescribed.

2. The loop-guide c, in combination with the looper, for laying theloop, as described.

3. The guard-pin c, or its equivalent, for the purpose set forth.

T. J. WV. ROBERTSON.

lVitnesses:

J. P. PINssER, S. H. MAYNARD.

